I am about to finish kitchen remodel. HO wanted to have under cabinet lights and also lights on top of the cabinets. Both will be controlled by one switch. I need something slim for under cabinet, something I can cut to size as cabinets are in sections, should be on "cold" side 4500 - 5000k.

Looks like a good place to put LED tape light. Get one of those slimline U channels. The low voltage wiring can be run a in tighter places than 120VAC. Driver could be located above the cabinets. Get the tape light itself in the color you like. I've used 4500k from Hafele, was pleased.

It depends on exactly which product you're working with. When you've got a bulky transformer with a traditional plug-in, I'll mount outlets in strategic locations in the back of 2 or 3 cabinets for the transformers to plug in to. Then run the low voltage lines cleverly down through the cabinets to the LED lights below.

If that's the case now, I'd install "cut-in" electrical boxes wherever they make sense (probably in the same stud bay that the Romex whips are at now) in the backs of cabinets and put your hardware in there and run the low voltage lines down to the underside of the cabinets.

While you're at it, you might want to suggest installing "over cabinet" lights. As it is now, it looks a little dark up there and this kind of lighting looks killer at night as a night light.

I already notched tiles for wire under cabinet, counting the light will hide it. If I use strip it'll be visible and I do not want mess with adding el. boxes.... I will use LED light fixtures under and strip on top.

Yes, all is symmetrical, except for tiles not centered with oven.... I centered tiles on sink, but started tiling from side on oven wall. Found out few days after I finished tiling. Was staring at it, couldn't believe what I did....

When I researched this 18 months ago, the line voltage LED option I liked best was the Halo HU10, which is 4-3/8" wide by 3/4" thick, comes in five different lengths, and multiple units can be easily daisy chained: